A113890 Smallest prime of the form: all eights followed by prime(n). a(n)> prime(n). 0 if no such prime exists.
0, 83, 0, 887, 811, 88813, 88817, 8819, 823, 829, 8831, 8837, 88888841, 88843, 88888888888888888888888888888847, 853, 859, 8861, 8867, 888871, 88873, 88888879, 883, 88888888888889, 88897, 8101, 888103, 8888107, 888109
Offset: 1
Examples
a(4) = 887, as 87 is composite, prime(4) = 7.
Programs
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Maple
cat2 := proc(a,b) a*10^(max(1,ilog10(b)+1))+b ; end: A002282 := proc(n) 8*(10^n-1)/9 ; end: A113890 := proc(n) local p,a,n8 ; p := ithprime(n) ; for n8 from 1 to 120 do a := cat2(A002282(n8),p) ; if isprime(a) then return(a) ; fi ; od: RETURN(0) ; end: seq(A113890(n),n=1..35) ; # R. J. Mathar, Jan 31 2008
Extensions
More terms from R. J. Mathar, Jan 31 2008
Comments